Erythropoietic protoporphyria-1 is an inborn error of porphyrin metabolism caused by decreased activity of the enzyme ferrochelatase, the terminal enzyme of the heme biosynthetic pathway, which catalyzes the insertion of iron into protoporphyrin to form heme. EPP is characterized clinically by photosensitivity to visible light commencing in childhood, and biochemically by elevated red cell protoporphyrin levels (Todd, 1994).
Genetic Heterogeneity of Erythropoietic Protoporphyria
Also see X-linked erythropoietic protoporphyria (XLEPP; 300752), caused by mutation in the ALAS2 gene (301300) on chromosome Xp11, and EPP2 (618015), caused by mutation in the CLPX gene (615611) on chromosome 15q22. [from
OMIM]